旋膜式除氧器在水泥厂余热电站中的应用

水泥厂的余热电站与水泥窑运行密切相关,水泥窑的波动严重影响了电站锅炉给水的除氧效果。文中通过对水泥厂余热电站选用的除氧器及其除氧原理的介绍以及对除氧效果的分析,提出了在水泥厂余热电站中宜提倡使用除氧效果较好的旋膜式除氧器的建议。旋膜式除氧器可保证锅炉给水除氧效果,延长电站机组运行寿命。     

运用CFD模拟浮选柱内的流体流动

根据浮选柱内气液流动的特点,在气速与气含率的径向分布一致的基础上,建立了通用的计算浮选柱内流体流动模型,简便且较准确地模拟出了浮选柱内气液的流动状况,为浮选柱内气体发生器设计以及柱内返混的研究提供了依据和方法。     

Independent prediction of slip velocity and hold-up in liquid/liquid extraction columns

The correlation of slip velocity using a large bank of published data for pulsed perforated-plate, Karr reciprocating-plate, rotating disc and spray extraction columns is presented. Based on more than 3,700 data points with and without mass transfer, empirical equations not including hold-up for each of the columns are suggested which reproduce the slip velocity data over a wide range of variables. Explicit correlations for hold-up in both the loose and dense-packed regions of operation in spray columns are also presented which do not involve slip velocity. The equations presented are more exact and simpler to use than previous empirical correlations; these often involve the characteristic velocity which is difficult to accurately predict.     

氧化还原树脂除氧技术应用总结

概述了氧腐蚀和氧化还原树脂对软化水进行除氧的机理,详细介绍了氧化还原树脂除氧技术的实际应用及其运行状况。实践证明,该技术操作简单,能有效延长换热设备的使用寿命,经济效益显著。     

LIQUID PHASE BACKMIXING IN BUBBLE COLUMN REACTORS—A NEW CORRELATION

Bubble column reactors are widely used in many industrial applications due to their simplicity of operation. Although simple to operate, bubble columns are difficult to scale-up due to the uncertainties in the estimation of some non-adjustable design parameters. One of these design parameters is the liquid phase backmixing.

The present work proposes a new correlation to estimate the liquid phase backmixing in bubble column reactors. The correlation is based on principles originally developed for flow through porous media and uses experimental data obtained over a wide range of operating conditions. This correlation is simple to use and requires parameters which are easily available or can be measured on a small scale apparatus. The proposed correlation shows a significant improvement over available literature correlations and is applicable to three phase systems as well.     

热力除氧辅助化学除氧技术的工业应用

介绍了云南云天化国际化工股份有限公司云峰分公司硫酸厂废热锅炉给水热力除氧系统存在的问题和改进措施。采用热力除氧辅助二甲基酮肟法化学除氧后,除氧水ρ(O2)≤0.015 mg/L,200 kt/a和300 kt/a硫酸装置锅炉水指标均达到正常生产要求。今后可考虑将热力除氧温度降低6～7℃,综合除氧成本将降低0.6元/t,预计改进后硫酸厂每年可节省运行费用约63万元。     

双塔串联中间储罐液相交换精馏操作及模拟

提出了一种用中间储罐来实现双塔串联液相交换的操作方式,可以用来分离相对挥发度小的物系或是热敏性物系。通过对乙醇-异丙醇物系的分离试验,验证了该操作方式的可行性,并且构建了全回流过程和塔间液相交换过程的数学模型,通过对模型的求解和与试验结果对比,论证了该模型能比较真实地模拟双塔串联中间储罐液相交换过程。     

径向基函数神经网络在精馏塔软测量中的应用

精馏塔是化工过程中最常用的操作单元 ,具有很强的非线性和时变性 ,故很难进行机理建模分析或常规在线实时控制 ,因而提出一种基于径向基函数神经网络的优化控制方案。通过利用径向基函数神经网络建立精馏塔产品质量的软测量模型 ,将软测量结果与现场数据比较 ,表明本模型具有比较准确的跟踪显示效果 ,并将软测量模型进一步应用到精馏塔的回流量和釜液排放量的优化控制中     

Prediction of dispersed phase holdup in pulsed disc and doughnut solvent extraction columns under different mass transfer conditions

Using experimental data from a number of pulsed disc and doughnut solvent extraction columns,a unified correlation for the prediction of dispersed phase holdup that considers the effects of mass transfer is presented.Pulsed disc and doughnut solvent extraction columns(PDDC) have been used for a range of important applications such as uranium extraction and nuclear fuel recycling.Although the dispersed phase holdup in a PDDC has been presented by some researchers,there is still the need to develop a robust correlation that can predict the experimental dispersed phase holdup over a range of operating conditions including the effects of mass transfer direction.In this study,dispersed phase holdup data from different literature sources for a PDDC were used to refit constants for the correlation presented by Kumar and Hartland [Ind.Eng.Chem.Res.,27(1988),131–138] which did not consider the effect of column geometry.In order to incorporate the characteristic length of the PDDC(i.e.the plate spacing),the unified correlation for holdup proposed by Kumar and Hartland based on data from eight different types of columns [Ind.Eng.Chem.Res.,34(1995) 3925–3940] was refitted to the PDDC data.New constants have been presented for each holdup correlation for a PDDC based on regression analysis using published holdup data from PDDCs that cover a range of operating conditions and physical properties and consider the direction of mass transfer.     

CFBB锅炉燃烧方案设计及现场应用案例

以130t／hCFB锅炉为研究对象,介绍DCS系统配置、功能及锅炉燃烧控制方案。针对CFB锅炉燃烧过程的复杂特性,基于多变量频域解耦控制理论,提出了“能量一氧量”双交叉燃烧控制方案,实现了CFB锅炉主要参数之间的解耦控制,消除了燃烧过程中主要内扰的影响,同时保证了燃烧的经济性,进而提高了锅炉燃烧自动控制系统的连续投运率,达到锅炉燃烧自动投运率为100％。     

热耦蒸馏技术进展

热耦蒸馏作为一种新型蒸馏技术,与常规蒸馏相比,热耦蒸馏平均可节省能耗30％左右,同时还可降低设备投资。本文介绍热耦蒸馏塔的构造、分类、特点以及设计和应用。     

合成氨锅炉给水溶解氧超标原因分析及对策

针对锅炉水除氧器出口溶解氧超标的问题,分析了溶解氧的危害及其腐蚀机理,并结合以往生产经验,从设备故障、工艺运行及分析测定等几个方面进行讨论分析,查找出溶解氧超标原因,并根据不同情况采取相应措施,解决生产问题,效果良好。     

除氧方法的发展与比较

介绍几种常见的锅炉给水除氧方法的分类、基本原理以及发展状况；对其优缺点和应用范围等进行粗略比较；提出选择适用除氧方法的建议。     

精馏塔的故障诊断方案设计

本文简单地介绍了精馏塔故障诊断的必要性。主要讨论了精馏塔的故障诊断专家系统和故障诊断的具体步骤(其中主要包括建立设备档案、确定检测方法、检测周期及维修时间和性能预测及档案管理)。只有将维修技术、故障诊断技术和计算机远程监测技术有机的结合，才能有效地预防和避免事故、优化操作条件和延长操作周期，为企业取得更大的经济效益和社会效益。     

An ion-exchange process with thermal regeneration. X. Removal of dissolved oxygen from the feedwater

Weakly basic amine resins are an essential component of thermally regenerable systems, but they have the inherent disadvantage of oxidation under the hot regeneration conditions unless oxygen is removed from the feed water. Removal of oxygen from the hot (80–90°C) regeneration water poses few problems, but the reduction of oxygen to the level of 0.05–0.1 mg/l required in the ambient temperature feed water is a relatively costly operation. This is now considered essential to achieve a long operating life for the resin. Techniques employed to date include vacuum deaeration either alone, or as a roughing stage followed by treatment with electrolytically generated ferrous ion. This note describes the successful demonstration of a method utilizing countercurreni contact with natural gas which, in suitable geographical areas, promises lower capital and operating costs.     

300kt／a甲醇精馏工序设计及运行总结

采用三塔精馏制取甲醇,设备配置合理、运行稳定、能耗低。产品纯度高,能达到GB和从级精甲醇质量。     

Effects of Liquid Holdup in Condensers on the Start‐Up of Reactive Distillation Columns

Compared with start‐ups in conventional distillation columns, those in reactive distillation (RD) columns are much more time and energy consuming, and generate a large amount of by‐products which are not easy to deal with together. For several years, researchers have been trying out different methods to shorten the time required to lower the cost of the start‐up. In this work, a rigorous dynamic model in the ChemCAD simulator is applied to model the start‐up process for the esterification of ethyl acetate in a reactive distillation column. In the model, two sets of equations are employed: one for the fill‐up and heating stage and the other for the equilibration process which follows. In the fill‐up and heating stage, fluctuation curves of the reboiler temperatures with respect to time which are similar to those for conventional distillation columns are observed, while in the equilibration process it is found that the increase of the liquid holdup volume in the condenser reduces the time required to reach steady state for the reactive column and decreases the liquid holdup volume in the reboiler at the equilibrium state. This shows that the liquid holdup volume in the condenser has an important effect on the start‐up of reactive distillation columns.     

Statistical key variable analysis and model-based control for the improvement of thermal efficiency of a multi-fuel boiler

Burning multi-fuel, including gases, liquid fuels and coal, whose flow rates and heating values vary all the time, a typical boiler in the steel and iron plant poses a challenge to achieving optimal operation. The present study proposes to develop an adaptive data-driven thermal efficiency estimator of multi-fuel boilers based on statistical identification of key variables. With the available on-line efficiency model, the model-based controller is hence readily applicable to improve the boiler efficiency. Real operation data taken from two industrial boilers are used to verify the effectiveness of the proposed method. The first half part of data serves to develop statistical models while the second half part serves to be simulated as virtual plants. The application of the proposed methods improved 1.94% of the thermal efficiency of a boiler burning multi-gas and 0.73% of a boiler burning coal and multi-gas in the virtual plant simulations.     

Overall efficiency evaluation of commercial distillation columns with valve and dualflow trays

The main objective of this work is to establish appropriated ways for estimating the overall efficiencies of industrial distillation columns with valve trays with downcomer and dualflow trays. The knowledge of efficiencies has fundamental importance in the design and performance evaluation of distillation columns. Searching in the literature, a tree of alternatives was identified to compose the tray efficiency model, depending on the mass transfer models, the liquid distribution and vapor flow models on the tray, the liquid entrainment model, the multicomponent mixture equilibrium model, the physical properties models, the height of froth on the tray model and the efficiency definition. In this work, different methods to predict the overall efficiency of distillation columns with valve and dualflow trays were composed and compared with data from three commercial distillation columns under different operating conditions. The models were inserted in the Aspen Plus 12.1 simulator, in Fortran language, together with tray geometrical data, fluid properties and operating data of the distillation columns. For each column, the best thermodynamic package was chosen by checking the temperature profile and overhead and bottom compositions obtained via simulation against the corresponding actual data of industrial columns. A modification in the fraction of holes evaluation that is jetting parameter of the Garcia's hydraulic model of dispersion above the tray was proposed. This modification produced better results than the original model to predict the fraction of holes that are jetting and in the efficiency of dualflow trays and similar results to Garcia model in the efficiency evaluation of valve trays. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

工业锅炉给水除氧方式探讨

在锅炉给水中,溶有多种气体,其中对热力设备危害最大的是溶解氧.在热力系统中,由于水汽温度都较高,使得金属受热面氧腐蚀的速度进一步加快,威胁锅炉运行.因此,国家技术监督局对各类锅炉水质有对应的法规标准进行规范,在设计中选择适合工程特点除氧方式是设计者经常面对的难题.对常用的热力除氧、真空除氧、化学除氧、解吸除氧等技术进行了分析比较,与设计同行探讨.